System and method for monitoring semiconductor device manufacturing process

• US 20090231424A1
• Filed: 02/26/2009
• Published: 09/17/2009
• Est. Priority Date: 02/29/2008
• Status: Active Grant

• Current Assignee: Hitachi High-Tech Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi High-Technologies Corporation (Hitachi, Ltd.)
• Inventors: Takagi, Yuuji, Honda, Toshifumi
• Granted Patent: US 8,547,429 B2
• Time in Patent Office: Days
• US Class Current: 348/87
• CPC Class Codes: G06T 2207/10061 from scanning electron microscope
• CPC Class Codes: G06T 2207/30148 Semiconductor; IC; Wafer
• CPC Class Codes: G06T 7/0006 using a design-rule based approach
• CPC Class Codes: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A hotspot searching apparatus manufactures a small number of chips or regions on a semiconductor wafer under respectively different manufacturing process conditions, compares SEM images of their external appearances to output a point having large differences as a narrow process window, that is, a process monitoring point that should be managed in mass production, the narrow process window having a narrow manufacturing process condition (exposure condition) in the manufacturing of the semiconductor wafer, and sets the point as a measurement point by a CD-SEM apparatus, such that it extracts and determines plural circuit pattern parts having a narrow manufacturing process margin as the process monitoring point in a short time and a process monitoring point monitoring performs shape inspection or shape length measurement in detail at high resolution.

Claims

1. A manufacturing process monitoring system comprising:

a hotspot searching apparatus including a SEM apparatus and an SEM image processing unit that processes SEM images obtained by imaging a semiconductor wafer whose surface is formed with patterns by the SEM apparatus and searches for process monitoring points; and

a process monitoring point monitoring apparatus for evaluating the shapes or dimensions of circuit patterns of the process monitoring points searched by the hotspot searching apparatus,

wherein the hotspot searching apparatus images the semiconductor wafer having a plurality of regions where circuit patterns have been formed under different manufacturing process conditions by the SEM apparatus, processes the SEM images of every region obtained by imaging the semiconductor wafer by the SEM image processing unit to obtain differences, extracts points where the differences exceed a reference value as process monitoring point candidates, and narrows-down the extracted process monitoring point candidates, so as to search for the processing monitoring points, and

the process monitoring point monitoring apparatus images the images of the process monitoring points on the basis of the process monitoring points having been searched by the hotspot searching apparatus and evaluates the shapes or dimensions of circuit patterns of the process monitoring points on the basis of the imaged images, in a region on a semiconductor wafer different from the semiconductor wafer on which the processing monitoring points have been searched or a region different from the region on the semiconductor wafer.

2. The manufacturing process monitoring system according to claim 1,

wherein the hotspot searching apparatus is configured to perform alignment between the SEM image of a predetermined imaged region and an image obtained from design data such that the extracted process monitoring point candidates and the design data can be compared.

3. The manufacturing process monitoring system according to claim 1, wherein:

when the SEM images of every region are compared to obtain a difference, the hotspot searching apparatus extracts edge parts of individual circuit patterns from the SEM images of every region and compares the extracted edge parts, so as to obtain the difference.

4. The manufacturing process monitoring system according to claim 1,

wherein the hotspot searching apparatus includes a graphic user interface for displaying the extracted process monitoring point candidates.

5. The manufacturing process monitoring system according to claim 4,

wherein the graphic user interface displays extraction regions obtained by a lithographic simulation of the design data together with the process monitoring point candidates at the same time.

6. The manufacturing process monitoring system according to claim 1, wherein:

the process monitoring point monitoring apparatus is composed of a CD-SEM apparatus.

7. A manufacturing process monitoring system comprising:

a SEM image acquiring unit for acquiring SEM images of a sample by imaging the sample;

a process monitoring point searching unit that processes SEM images obtained by imaging, as the sample, a first semiconductor wafer whose surface is formed with patterns by the SEM image acquiring unit and searches for regions for monitoring a process of forming the patterns; and

a process monitoring point monitoring unit that evaluates shapes or dimensions of patterns formed on a second semiconductor wafer from SEM images obtained by imaging a second semiconductor wafer by the SEM image acquiring unit on the basis of information on regions for monitoring the process having been searched by the process monitoring point searching unit,

wherein the process monitoring point searching unit processes the SEM images of every region obtained by imaging the first semiconductor wafer having the plurality of regions on which the patterns have been formed by the SEM image acquiring unit under different process conditions and searches for regions for monitoring the process.

8. The manufacturing process monitoring system according to claim 7,

wherein the searching of the regions for monitoring the process by processing the SEM images of every region by the process monitoring point searching unit is performed by processing the SEM images of every region obtained by imaging the first semiconductor wafer by the SEM image acquiring unit to obtain differences, extracting regions including points where the obtained differences exceed a reference value as candidates of the regions for monitoring the process, and narrowing-down the extracted candidates of the regions for monitoring the process.

9. The manufacturing process monitoring system according to claim 7,

wherein the process monitoring point searching unit searches for the regions for monitoring the process by using a SEM image of a predetermined region on the first semiconductor wafer imaged by the SEM image acquiring unit and an image obtained from design data corresponding to the predetermined region.

10. The manufacturing process monitoring system according to claim 7, wherein:

when the SEM images of every region are compared to obtain differences, the process monitoring point searching unit extracts the edge parts of the individual circuit patterns from the SEM images of every region and compares the extracted edge parts, so as to obtain the difference.

11. The manufacturing process monitoring system according to claim 7,

wherein the process monitoring point searching unit includes a graphic user interface for displaying the extracted process monitoring point candidates.

12. The manufacturing process monitoring system according to claim 11,

wherein the graphic user interface displays extraction regions obtained by a lithographic simulation of the design data together with the process monitoring point candidates at the same time.

13. The manufacturing process monitoring system according to claim 7,

wherein the process monitoring point monitoring unit includes a CD-SEM apparatus.

14. A manufacturing process monitoring method comprising:

imaging, as a sample, a first semiconductor wafer whose surface is formed with patterns by an SEM image acquiring unit and acquiring the SEM image of the first semiconductor wafer;

processing the acquired SEM images of the first semiconductor wafer to search for regions for monitoring a process of forming the patterns;

imaging a second semiconductor wafer by the SEM image acquiring unit, on the basis of information on the searched regions for monitoring the process; and

processing the SEM images of the regions for monitoring the process obtained by imaging the second semiconductor wafer and evaluating shapes or dimensions of patterns formed on the second semiconductor wafer,

wherein, the searching for the regions for monitoring the process processes the SEM images of every region obtained by imaging the first semiconductor wafer having the plurality of regions on which the patterns have been formed by the SEM image acquiring unit under different process conditions and searches for regions for monitoring the process.

15. The manufacturing process monitoring method according to claim 14,

wherein in the searching for the regions for monitoring the process, the searching of the regions for monitoring the process by processing the SEM images of every region is performed by processing the SEM images of every region obtained by imaging the first semiconductor wafer by the SEM image acquiring unit to obtain differences, extracting regions including points where the obtained differences exceed a reference value as candidates of the regions for monitoring the process, and narrowing-down the extracted candidates of the regions for monitoring the process.

16. The manufacturing process monitoring method according to claim 14,

wherein in the searching for the regions for monitoring the process, the regions for monitoring the process are searched by using the SEM images of a predetermined region on the first semiconductor wafer imaged by the SEM image acquiring unit and images obtained from design data corresponding to the predetermined region.

17. The manufacturing process monitoring method according to claim 14,

wherein in the searching for the regions for monitoring the process, when the SEM images of every region are compared to obtain differences, edge parts of individual circuit patterns are extracted from the SEM images of every region and the extracted edge parts are compared, so as to obtain the difference.

18. The manufacturing process monitoring method according to claim 14,

wherein in the searching for the regions for monitoring the process, the extracted process monitoring point candidates are displayed on a screen by a graphic user interface.

19. The manufacturing process monitoring method according to claim 18,

wherein the graphic user interface displays extraction regions obtained by a lithographic simulation of the design data together with the process monitoring candidates at the same time.

20. The manufacturing process monitoring method according to claim 14,

wherein in the evaluating shapes or dimensions of patterns formed on the second semiconductor wafer, the SEM images of the regions for monitoring the process obtained by imaging the second semiconductor wafer is acquired by using a CD-SEM.